InfrastructureUnderwater ears offer information about hurricane strength

Published 10 April 2008

MIT researchers find that hydrophones planted on the ocean floor can “listen” to hurricanes as they form; the sound hurricanes make varies with their intensity — so early listening to hurricanes would help first responders better prepare

You can hear a hurricane — or, at least, hurricanes make
themselves heard, even under water. Why, then, not use that sound safely to
gauge how destructive a storm will be before it makes landfall? Joshua Wilson
and Nicolas Makris at the Massachusetts Institute of Technology reckoned that the
frequency of the underwater din of a hurricane whipping up waves might
correspond to its intensity. They took recordings made by an underwater
listening device called a hydrophone placed on the floor of the mid-Atlantic
during Hurricane Gert in 1999, and compared these readings with concurrent satellite
data and wind speed measurements made by U.S. military aircraft. As Gert passed
over the hydrophone, the frequency of the noise peaked twice, corresponding to
the strong winds on either side of the storm’s eye as it passed over. The team
found that the frequency of the underwater sound correlated to the cube of the
wind speed recorded by the aircraft. The researchers note that planting
hydrophones in hurricane-prone regions would be cheaper and safer than using
aircraft to gauge their intensity, but just as accurate. They could be really
useful in regions such as the Pacific and Indian Oceans, where specialised
aircraft are often not available.